1. Field of the Invention
The invention relates to a method for separating a bearing channel of a housing by cracking and a cracking unit by which such separation by cracking can be carried out.
2. Discussion of the Related Art
The separation by cracking of connecting rods of an internal combustion engine has been employed for quite a long time already. In the connecting rod top end to be separated by cracking two diametrally disposed notches predetermining the separating plane by cracking are introduced by means of laser. Subsequently the connecting rod top end is separated by cracking by a cracking mandrel and a cover is separated from the connecting rod. This cracking method has practically been prevailing as standard worldwide.
During the past few years, apart from the afore-described connecting rods also housings provided with bearing arrangements, for instance a crankcase of an internal combustion engine, have been started to be separated by cracking, wherein the bearing covers of a bearing channel supporting a crankshaft are separated from a respective bearing block formed on the housing. A method of this type is described in DE 199 11 598 A1. A cracking mandrel by which a cracking force is applied to the bearing cover is introduced into the bearing channel, wherein the cracking plane is in turn predetermined by notches introduced by means of laser energy or broaching.
During the finish of both connecting rods and housings an excessive deformation in the area of the separating plane by cracking can be avoided when the separated bearing cover or, for instance during connecting rod cracking, the connecting rod cover are supported.
Especially during the finish of housings including a bearing channel in which a plurality of bearing covers have to be separated from the allocated bearing blocks, a problem consists in allocating the separated bearing covers to the corresponding bearing blocks after the separation by cracking. In the solution known from DE 199 11 598 A1 the bearing covers are supported during a separating operation by cracking by means of a reinforcing means bridging the bearing cover which is screwed into the bearing cover and the bearing block by studs. After separation by cracking this reinforcing means has to be removed by loosening the studs so that the then loose bearing covers subsequently have to be attached again. For this allocation of the bearing covers to the respective bearing block considerable process expenditure is necessary which makes the manufacture of the housing more expensive. Moreover, it is also extremely complicated to fix the reinforcing means by means of the bearing bolts, which further increases the manufacturing costs.